#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>

void func(int* x, int* y)
{
	int* p;
	*p = *x;
	*x = *y;
	*y = *p;
}

int main()
{
	int a = 10;
	int b = 20;
	func(&a, &b);
	printf("%d %d", a, b);

	return 0;
}